rocksdb/utilities/transactions/optimistic_transaction_impl.cc
Manuel Ung 9300ef5455 Fix shared lock upgrades
Summary:
Upgrading a shared lock was silently succeeding because the actual locking code was skipped. This is because if the keys are tracked, it is assumed that they are already locked and do not require locking. Fix this by recording in tracked keys whether the key was locked exclusively or not.

Note that lock downgrades are impossible, which is the behaviour we expect.

This fixes facebook/mysql-5.6#587.
Closes https://github.com/facebook/rocksdb/pull/2122

Differential Revision: D4861489

Pulled By: IslamAbdelRahman

fbshipit-source-id: 58c7ebe7af098bf01b9774b666d3e9867747d8fd
2017-04-10 16:06:00 -07:00

143 lines
4.4 KiB
C++

// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
#ifndef ROCKSDB_LITE
#include "utilities/transactions/optimistic_transaction_impl.h"
#include <algorithm>
#include <string>
#include <vector>
#include "db/column_family.h"
#include "db/db_impl.h"
#include "rocksdb/comparator.h"
#include "rocksdb/db.h"
#include "rocksdb/status.h"
#include "rocksdb/utilities/optimistic_transaction_db.h"
#include "util/string_util.h"
#include "utilities/transactions/transaction_util.h"
namespace rocksdb {
struct WriteOptions;
OptimisticTransactionImpl::OptimisticTransactionImpl(
OptimisticTransactionDB* txn_db, const WriteOptions& write_options,
const OptimisticTransactionOptions& txn_options)
: TransactionBaseImpl(txn_db->GetBaseDB(), write_options), txn_db_(txn_db) {
Initialize(txn_options);
}
void OptimisticTransactionImpl::Initialize(
const OptimisticTransactionOptions& txn_options) {
if (txn_options.set_snapshot) {
SetSnapshot();
}
}
void OptimisticTransactionImpl::Reinitialize(
OptimisticTransactionDB* txn_db, const WriteOptions& write_options,
const OptimisticTransactionOptions& txn_options) {
TransactionBaseImpl::Reinitialize(txn_db->GetBaseDB(), write_options);
Initialize(txn_options);
}
OptimisticTransactionImpl::~OptimisticTransactionImpl() {
}
void OptimisticTransactionImpl::Clear() {
TransactionBaseImpl::Clear();
}
Status OptimisticTransactionImpl::Prepare() {
return Status::InvalidArgument(
"Two phase commit not supported for optimistic transactions.");
}
Status OptimisticTransactionImpl::Commit() {
// Set up callback which will call CheckTransactionForConflicts() to
// check whether this transaction is safe to be committed.
OptimisticTransactionCallback callback(this);
DBImpl* db_impl = dynamic_cast<DBImpl*>(db_->GetRootDB());
if (db_impl == nullptr) {
// This should only happen if we support creating transactions from
// a StackableDB and someone overrides GetRootDB().
return Status::InvalidArgument(
"DB::GetRootDB() returned an unexpected DB class");
}
Status s = db_impl->WriteWithCallback(
write_options_, GetWriteBatch()->GetWriteBatch(), &callback);
if (s.ok()) {
Clear();
}
return s;
}
Status OptimisticTransactionImpl::Rollback() {
Clear();
return Status::OK();
}
// Record this key so that we can check it for conflicts at commit time.
//
// 'exclusive' is unused for OptimisticTransaction.
Status OptimisticTransactionImpl::TryLock(ColumnFamilyHandle* column_family,
const Slice& key, bool read_only,
bool exclusive, bool untracked) {
if (untracked) {
return Status::OK();
}
uint32_t cfh_id = GetColumnFamilyID(column_family);
SetSnapshotIfNeeded();
SequenceNumber seq;
if (snapshot_) {
seq = snapshot_->GetSequenceNumber();
} else {
seq = db_->GetLatestSequenceNumber();
}
std::string key_str = key.ToString();
TrackKey(cfh_id, key_str, seq, read_only, exclusive);
// Always return OK. Confilct checking will happen at commit time.
return Status::OK();
}
// Returns OK if it is safe to commit this transaction. Returns Status::Busy
// if there are read or write conflicts that would prevent us from committing OR
// if we can not determine whether there would be any such conflicts.
//
// Should only be called on writer thread in order to avoid any race conditions
// in detecting write conflicts.
Status OptimisticTransactionImpl::CheckTransactionForConflicts(DB* db) {
Status result;
assert(dynamic_cast<DBImpl*>(db) != nullptr);
auto db_impl = reinterpret_cast<DBImpl*>(db);
// Since we are on the write thread and do not want to block other writers,
// we will do a cache-only conflict check. This can result in TryAgain
// getting returned if there is not sufficient memtable history to check
// for conflicts.
return TransactionUtil::CheckKeysForConflicts(db_impl, GetTrackedKeys(),
true /* cache_only */);
}
Status OptimisticTransactionImpl::SetName(const TransactionName& name) {
return Status::InvalidArgument("Optimistic transactions cannot be named.");
}
} // namespace rocksdb
#endif // ROCKSDB_LITE